finally got dyno'd and something is up

[RED09GT]

It seems too repeatable to me for it to be the clutch slipping in the exact same window and then getting enough grip again in all 3 runs.
Could it be a glitch in the dyno or the software? Did the car show any hesitation visually or audibly during the runs?

 

[Riptide]

What should be the outcome? I have always tested clutch by rev up and dumping it it first through 2nd tach will tell and tires should smoke right through.

If you have a problem you can tell w/the 5th gear test because the revs will climb faster than they should while the car doesn't accelerate much if at all.

I've also been told you can get the car going in 3rd gear, up into the revs, and then let off the throttle and stab it over and over. The car should buck and lurch if it's holding. If it seems sloppy then it probably has an issue.

I've also heard dumping it in 3rd gear can be done to test for slip. It should stall. If it doesn't then you have a problem.

 

[VanWilder]

What should be the outcome? I have always tested clutch by rev up and dumping it it first through 2nd tach will tell and tires should smoke right through.

When doing this the clutch doesnt slip at all...tires will spin through redline in 2nd no problem

It's in the tune man, you should be at about 340rwhp

I agree...I talked to the owner of the dyno again last night and he said its definately not clutch slip because of the way the dip was if it was a slip it wouldnt have kept climbing after the dip...the torque would have leveled out

definitely sounds like its time for a clutch. that dip in the torque could be where the clutch is really starting to lose its hold. especially since you have 60+k miles on it. put in an exedy mach 500 (basically a roush p51) and you should see a drastic change in your numbers. also make sure your pinion angle is correct especially since youre dropped so low. every degree that your off is equal to a loss of about 10 hp. have you done anything to the suspension besides lower it? control arms especially? if not you will want to look at the adjustable upper at least.

I agree its definately time for a clutch mainly because of miles but there are no signs of it slipping while driving...in any gear...as for pinion angle I agree as well I definately need to me getting some adjustable upper contol arms and lower as well...will you really see a 10rwhp loss for every degree its off...how many degrees off do you think mine would be with that much of a drop??

It seems too repeatable to me for it to be the clutch slipping in the exact same window and then getting enough grip again in all 3 runs.
Could it be a glitch in the dyno or the software? Did the car show any hesitation visually or audibly during the runs?

Thats exactly what I was thinking too...as far as a glitch in the dyno software...I doubt it...and yes on the dyno at 3800 you could hear a slight change in the exhaust tone when the dip occoured and you can hear it on the street as well...I've never noticed it before because usually when I'm on it hard 4th gear never sees 3800 rpm

If you have a problem you can tell w/the 5th gear test because the revs will climb faster than they should while the car doesn't accelerate much if at all.

I've also been told you can get the car going in 3rd gear, up into the revs, and then let off the throttle and stab it over and over. The car should buck and lurch if it's holding. If it seems sloppy then it probably has an issue.

I've also heard dumping it in 3rd gear can be done to test for slip. It should stall. If it doesn't then you have a problem.

well we did a 5th gear run on the dyno and it climbed just fine all the way to 180mph so I dont think its a slipping issue

 

[tillman speed]

Have him look at "gear ratio" which looks at both MPH and rpm... if he sens me the DRF dynojet run file, then I can look at that and tell you whether or not something is slipping for sure... without guessing.

Gear ratio should be a nice smooth downward slope, and if you get some sort of a spike upwards when that error happens, more than likely we're looking at a mechanical issue between the motor and the dyno roller. If it doesn't then we're probably looking at something VCT related. I've sent this same tune file out to hundreds of people running this cam and phaser limiters with great results, so I'm hoping we can find out what the problem is. I built the VCT map for that cam on the dyno.

 

[tillman speed]

Just one quick sidenote: I know you're running HT0's, because you plan on going with nitrous shortly. You're currently running them with the out-of-the-box gap? Or are they gapped down? With nitrous, I usually just throw them in. I really only gap them with a really large nitrous shot or with a blower. Anything under 100-125 shot doesn't need to be gapped.

Let me know, because I'm wondering if it could be some sort of spark blowout that it pushes through. Did you try throwing in a fresh set of HT1's or a clean stock heat range plug?

 

[VanWilder]

Have him look at "gear ratio" which looks at both MPH and rpm... if he sens me the DRF dynojet run file, then I can look at that and tell you whether or not something is slipping for sure... without guessing.

Gear ratio should be a nice smooth downward slope, and if you get some sort of a spike upwards when that error happens, more than likely we're looking at a mechanical issue between the motor and the dyno roller. If it doesn't then we're probably looking at something VCT related. I've sent this same tune file out to hundreds of people running this cam and phaser limiters with great results, so I'm hoping we can find out what the problem is. I built the VCT map for that cam on the dyno.

Hey man!! I sent you the DRF files last night...did they not go through??

 

[VanWilder]

Just one quick sidenote: I know you're running HT0's, because you plan on going with nitrous shortly. You're currently running them with the out-of-the-box gap? Or are they gapped down? With nitrous, I usually just throw them in. I really only gap them with a really large nitrous shot or with a blower. Anything under 100-125 shot doesn't need to be gapped.

Let me know, because I'm wondering if it could be some sort of spark blowout that it pushes through. Did you try throwing in a fresh set of HT1's or a clean stock heat range plug?

Yes I am running them right now with the out of the box gap...I was told with the 100 shot I would need to gap them down to .032-.035....no I havent tried throwing in a fresh set of HT1s or clean stock heat range plugs because I dont have any at this time...especially since they are $80+ for a set...I would throw my stockers back in but I broke 2 when they were uninstalled...oh and btw I'm on hold waiting to talk to you lol

 

[tillman speed]

Something is going on there between the rollers and the motor. Pinion angle, clutch, something.

Keep the factory gap on the HT0's until you have nitrous on the car, then for 100 shot maybe clamp em down to 35-40 if you want to feel safe. I usually gap at 125 shot or so. But closing the gap ain't gonna hurt anything, that's for sure!

 

[Riptide]

Pinion angles gonna be a lot cheaper and easier to fix than a clutch. I'd start with that.

 

[VanWilder]

Pinion angles gonna be a lot cheaper and easier to fix than a clutch. I'd start with that.

I'm gonna do both...the clutch has 64000 hard miles on it and obviously the pinion angle needs fixed...I found the clutch I'm gonna go with its a Fidanza Stage 4.3...ultrarev.com has it for $265 which is damn near half the cost of most the others I have been looking at

 

[smoken1986]

I'm gonna do both...the clutch has 64000 hard miles on it and obviously the pinion angle needs fixed...I found the clutch I'm gonna go with its a Fidanza Stage 4.3...ultrarev.com has it for $265 which is damn near half the cost of most the others I have been looking at

Do your research on the clutch for your car and dont cheap out it will cost you more in the long run. I am not saying the one you are looking at is bad because I dont know anything about it, but many have paid the price for not listening to others mistakes. And being you are putting a 100 shot on it you will need a good clutch. I would recomend the p51 disc if you are running a 3650. But thats just my opinion

 

[VanWilder]

Do your research on the clutch for your car and dont cheap out it will cost you more in the long run. I am not saying the one you are looking at is bad because I dont know anything about it, but many have paid the price for not listening to others mistakes. And being you are putting a 100 shot on it you will need a good clutch. I would recomend the p51 disc if you are running a 3650. But thats just my opinion

I completely agree with you man!!! I'm definately looking to see whats available but I'm needing a good deal as well

 

[irishpwr46]

get in touch with bbr and go with the exedy mach 500. it comes with a new slave and everything